The invention relates to a printing method for producing a print image on a carrier material, in which a print carrier is provided whose surface is charged with water vapor in a manner corresponding to the structure of the print image to be printed.
In known printing methods, such as the offset printing method, partial printing regions corresponding to the print image to be printed are provided on the surface of a print carrier, e.g. a print plate, a printing strip or a print master, which regions are inked with ink during the print process and subsequently print the carrier material with the ink. Various methods are known for the formation of these partial printing regions. For example, in the direct imaging method of the company Heidelberger Druckmaschinen, a print master is produced on a silicon-coated film by partially burning away the silicon layer, and the silicon-free locations accept the ink during the print process and print the carrier material. In another known method, hydrophobic and hydrophilic regions corresponding to the structure of the print image to be printed are produced on the print carrier. Before the application of ink to the print carrier, a thin film of moisture is first applied to the print carrier using application rollers or, respectively, spraying systems, which film wets the hydrophilic regions of the print carrier. Subsequently, using an ink roller, ink is applied to the surface of the print carrier, which however uses exclusively the regions not covered with a film of moisture. After the inking of the print carrier, the inked print image is finally transferred to the carrier material.
From U.S. Pat. No. 3,072,049 and U.S. Pat. No. 2,002,815, printing systems are known that respectively operate according to a printing method in which in order to produce the thin film of moisture on the surface of the print carrier, instead of using application rollers or spraying systems water vapor is applied to the hydrophilic regions of the print carrier. Here as well, the surface of the print carrier, which is charged with water vapor, is divided into hydrophobic and hydrophilic regions corresponding to the structures of the print image to be printed.
The printing methods described above all have in common that a print carrier has to be used on a surface of which raised and flat regions, or hydrophobic and hydrophilic regions, are provided corresponding to the structures of the print image to be printed.